From the comments, on the value of management consultants

As a retired management consultant, some views on their stated value (as stated by clients, which is not necessarily the same as “value” as seen by other observers, e.g. Douglas Adams). 1. Consultants as temps. Keep own planning staff small, hire consultants when surge capacity needed. 2. New views. Yes, the young consultants may not know your industry well. This fresh look may actually be desired. In my own experience clients oscillated between “Give me people who actually know something about my business!” and “Stop giving me people from inside my world, they just tell me what I already know!” 3. Cowardice. Client knows he must lay off 5,000, call in consultants to figure that out, blame them for it. 4. Sounding boards. Senior executives believe it or not often have no one to talk to, who is not scheming to take their job or playing other politics. Consultants play politics of course, but they are at least transparent: “If I give you advice you find valuable you will hire me again.” 5. Pollination. The client cannot go and ask 5 rival firms what they think about developments in the industry, at least not easily. If the consultants have worked for many clients in the industry, they can transfer best ideas. If you like this, you call it “dissemination of best practices;” if you don’t like it, you call it “stealing and re-selling trade secrets to rivals”. 6. Complexity. A client on its own may not want to invest in learning all it needs about AI, IOT, Bitcoin, on and on. The consultant invests in this knowledge (McKinsey’s research budget is in at least 8 digits, including opportunity costs) and can deliver it packaged up for easy access by the client.

That is from Glenn Mercer.